Significance In the last half century, electronic devices and integrated circuits have achieved great success in information processing. Moore s Law states that the number of transistors in an integrated circuit doubles approximately every 18 months. However, electronic devices and circuits suffer from inherent problems such as resistance - capacitance time delay and thermal effects. According to Moore s Law, by 2020, fewer than one electron will be contained/included in a transistor, which severely limits the development of integrated circuits. Integrated photonics is considered one of the most promising technologies to replace integrated circuits in the post - Moore era. Compared with electronics, photons have advantages such as ultra - high transmission speeds, high parallelism, and wide bandwidths. Photons exist in a highly coherent state as bosons, allowing for parallel transmission without the fear of external interference. In addition, photons have relatively high information capacity and can carry signals at varying emission intensities, wavelengths, and polarization. Semiconductor micro - and nano - lasers are essential components in photonic integration systems as high - performance light sources. Renowned physicist Thomas M. Baer published an opinion in Nature stating that, in the future, scientists will achieve micro/nano - laser outputs with spot sizes of approximately 1 nm, which will facilitate ultra - high - resolution imaging and direct sequencing of biomolecules. Therefore, research on semiconductor micro - and nano - lasers is of significance in fields such as integrated displays, integrated photonics, optical information processing, and biological imaging. Semiconductor micro - and nano - lasers utilize wavelength - scale microcavities to achieve laser emission and have advantages such as small sizes, compact structures, and low cost, making them ideal choices for high - performance light sources. Particularly with the development of information technology and integrated optics, the design and fabrication of high - performance micro - and nano - laser sources have become increasingly important. Similar to macroscopic laser systems, the output of micro - and nano - lasers primarily depends on three components: resonant cavity, gain medium, and pump source. To date, advancements in these three aspects have been driving the progress and innovation of semiconductor micro - and nano - lasers. Currently, known resonant cavity structures include edge - emitting, vertical - surface - emitting, distributed Bragg reflector, microdisk, nanowire, microsphere, photonic crystal, and plasmonic cavities. In addition, they can be classified into random - cavity, Fabry - Perot cavity, and ring - cavity lasers as well as photonic crystal microlasers, distributed feedback cavity lasers, and surface plasmon microlasers based on their different resonance mechanisms. The gain media in semiconductor microand nanolasers mainly consist of organic dyes, quantum wells, quantum dots, and two - dimensional transition metal materials. Since the successful demonstration of optical gain in colloidal quantum dots (CQDs) twenty years ago, CQD - based lasers have rapidly developed. However, due to limitations imposed by the quality factors of microcavites, gain material, and spontaneous emission coupling efficiency, the reported outputs of semiconductor microand nanolasers have generally exhibited multimodal structures with poor monochromaticity, low Q - factors, and high thresholds. To achieve high - quality output from lowdimensional semiconductor microand nanolasers, the exploration of new high - gain semiconductor nanomaterials, innovative designs, and the fabrication of efficient novel microcavity structures are critical. This article considers the achievements and research progress in the field of lowdimensional semiconductor microand nanolasers and summarizes the research on microand nanolasers based on novel perovskite materials. Finally, the article provides an outlook on the developmental prospects of lowdimensional microand nanolasers. Progress When the sizes of semiconductor crystals reach a few nanometers, a quantum size effect occurs due to strong spatial confinement of charge carriers, which provides new possibilities for constructing novel and powerful optoelectronic devices. Semiconductor quantum dots are recognized as materials with superior optical gain as compared with bulk and quantum well materials. Unlike traditional top - down fabrication processes such as photolithography, the unique bottom - up synthesis approach of lowdimensional semiconductor materials not only simplifies the preparation of microand nanolasers but also provides high - quality selfresonant cavities. Perovskite nanomaterials, as a new type of semiconductor optoelectronic material, possess excellent optical properties and high carrier transport characteristics, making them ideal optical gain media for on - chip integrated microand nanolight sources. In the field of microand nanolasers, perovskite nanomaterials are mainly grouped into two categories: organic - inorganic hybrid structures and all - inorganic structures based on the ABX 3 structure. Studied nanostructures include nanoplates, nanowires, and quantum dots (Fig. 1). In 2014, Sum et al . published their findings on amplified spontaneous emission and lasing in MAPbX 3 thin - film materials, which initiated research on perovskite microand nanolasers. In 2015, Kovalenko s group reported for the first time spontaneous emission amplification phenomenon in all - inorganic CsPbBr 3 perovskite quantum dots. Since then, various lowdimensional semiconductor microand nanolasers have been reported based on different morphological structures, including microring cavities, cubic cavities, nanowires, nanoplates, and quantum dots (Fig. 2). In this article, the developmental status of lowdimensional semiconductor microand nanolasers is first introduced. The research progress of microand nanolasers is then presented based on different gain materials and structures, and their applications in fields such as quantum coding, optical anticounterfeiting, ultrafast optics, and other fields are described. Finally, we summarize the development of lowdimensional microand nanolaser and forecast future developmental trends. Conclusions and Prospects Low - dimensional semiconductor microand nanostructures serve as major platforms for studying the interaction between light and matter. Harnessing the mechanisms of microand nanostructures, high - performance research on microand nanolasers involves interdisciplinary collaboration across fields such as chemistry, materials science, and physics. This research has significant applications in areas such as microand nanolight sources, optical communication sensing, photonic computing, and quantum information processing. To achieve practical applications of lowdimensional semiconductor microand nanolasers through continuous wave pumping and electrical pumping, further exploration and analysis of the physical mechanisms and resonance modes involved in continuous wave pumping laser formation are essential. In addition, a systematic investigation of the requirements for material structures and gain properties under continuous wave pumping is necessary to ensure beam quality and stability of laser output. Finally, achieving electrical injection lasers requires thoughtful and extensively forward - looking research.
